This invention concerns a method of packing infusion bags in groups, especially for making tea, which are assembled in a predetermined number in a series of infusion bags and inserted into a packing container prepared in a predetermined position. The invention also concerns a device for implementing the method.
Methods and devices for continuous production of infusion bags and corresponding infusion bags are known in many embodiments. In one of the known embodiments, individual quantities of a substance to be extracted are deposited on a strip of filter paper and then a tube is formed that is divided into individual chambers closed on all sides, each containing a quantity of the substance. The tube is formed by overlapping and folding the strip of filter paper and closing it by means of a longitudinal seam or by adding another strip of filter paper and making two longitudinal seams. This forms a strand of chambers, which consists of continuous chambers, one after another, closed by a crosswise seam and containing a quantity of substance; the crosswise seam is also the back seam of one chamber and the front seam of the next one, and includes a perforation between the two seams where the chambers are separated during the process. The isolated chambers are then attached to a carrier material, which is used for handling and suspending the infusion bag. To make the carrier material forming the hanger of the infusion bag, a crosswise perforated strand of carrier material whose sections of carrier material form the hanger of the infusion bag in continuous production is used.
It is known how to pack and sell a predetermined number of infusion bags assembled in a series of bags, especially for making tea, in groups by inserting them in packing containers, especially boxes. Besides the continuous production of the infusion bag described above as an example, their packing should also be fully automatic. Due to the flux characteristics of the quantities of substance with which the infusion bags are filled, they preferably collect in the back part of the infusion bag in the direction of movement, so that the individual infusion bag, seen over the surface, has a different thickness, especially at high production capacity in the range of production from 800 to 1,500 infusion bags per minute. Overall, this produces a series of infusion bags with different sealed and thick zones, which runs counter to a basic interest in the smallest possible packing containers. It is also necessary to avoid an arrangement of infusion bags pressed too tightly in the packing containers, since otherwise they can be damaged when taken out.
With the known methods and devices, when stacking and packing infusion bags in groups, especially those for making tea, it is not possible to guarantee a high production rate and at the same time good equalization and compression of the tea packed in the bags, and so guarantee the possibilities of reducing the size of the package.
In view of this state of the art, the problem of the invention is to improve a method of stacking and packing infusion bags in groups, especially those for making tea, of the type mentioned at the beginning, in such a way that at high production capacities, uniform distribution and good compression of the quantities of substance with which the infusion bags are filled is possible over the entire surface of the infusion bag without pressing them down. It should also permit simple, reliable and especially damage-free stacking and packing of infusion bags at high production speeds. And the invention should also provide a technically simplified device for implementing the method.
The problem in the invention is solved with a method of the type mentioned at the beginning in which infusion bags arranged in a strand one after another in series in continuous production are separated, their speed of movement is reduced and they are put in a position suitable for making a stack, and the infusion bags are arranged one after another in such a way that they at least partly overlap in their subsequent direction of movement.
The invention is based on the knowledge of how to change the speed of movement of the infusion bags one after another in a strand in continuous production by changing the arrangement of the infusion bags. According to the invention, the distance between infusion bags one after another in a strand in continuous production is reduced by an overlapping arrangement of the infusion bags. According to the invention, at least two infusion bags are arranged on the length of an infusion bag by making a stack in the direction of movement due to the overlapping arrangement. The associated reduction in distance between infusion bags brings with it a reduction in speed, so the infusion bags move from continuous production to stacking and packing in groups with no noteworthy shock.
Advantageously, to separate an infusion bag from the strand, the continuously moved strand is grasped when the infusion bag to be separated is in a predetermined position, preferably near a perforation made in the side of the strand, and is accelerated in the direction of movement of the strand in such a way that the infusion bag is separated from the strand by the relative movement. Advantageously, the infusion bags in a crosswise perforated strand in continuous production are fed to a continually turning wheel, which has tongs placed on the side of the wheel that can move in relation to the wheel to grasp the longitudinal sides of the infusion bag to be separated from the strand at a predetermined position near the perforation, and the infusion bag can be separated by relative movement of the tongs to the wheel. Advantageously, the tongs can swivel in the direction in which the wheel turns and can accelerate to produce the relative movement in that direction. Advantageously, the tongs are accelerated by curve control.
To make a stack, in another advantageous embodiment of the invention, the separated infusion bags are deposited on the outer periphery of a continually turning partitioned wheel that has pouch-like receptacles for the infusion bags. The arrangement of infusion bags to one another is changed by the partitioned wheel so that the distance between them and hence their speed of movement is reduced. To adjust the speed of the infusion bags from the tonged wheel used for separating them to the partitioned wheel, the tong movement is returned after acceleration and the infusion bag speed is reduced, preferably via curve control. The speed is adjusted in such a way that the transfer of the infusion bags from the tonged wheel to the partitioned wheel takes place with no noteworthy shock, so good equalization and compression of the quantities of substance packed in the infusion bags is maintained.
Advantageously, the infusion bags are held in the pouch-like receptacles of the partitioned wheel by suction. This results in another homogenization of the quantities of substance contained in the infusion bags, and the infusion bags are kept safe at the same time.
Advantageously, the infusion bags are moved by turning the partitioned wheel on a rail support arranged on the side of the partitioned wheel, by means of which the infusion bags are automatically taken out of the receptacles on the partitioned wheel at defined distance from one another and stacked in a shaft. The infusion bags taken out of the receptacles in the partitioned wheel are stacked in the shaft by means of spiral conveyors arranged in the area near the longitudinal sides of the infusion bags. The spiral conveyors are used to maintain a certain distance between the individual infusion bags. To support the alignment of the quantities of substance in the infusion bags, shaking devices are advantageously provided, which set the stacked infusion bags in shaking motions to align the quantities of substance. A distance is produced between the infusion bags to be stacked by the spiral conveyors, and it is used in the rest of the process to assemble a predetermined number of infusion bags into a series of infusion bags. To move the infusion bags out of the partitioned wheel area, the spiral conveyor has a greater pitch in the area near the partitioned wheel.
To assemble a predetermined number of infusion bags into a series of infusion bags, a feeder is used to grasp infusion bags stacked some distance apart in the shaft by means of the spiral conveyors; it engages in the shaft, depending on the predetermined number of infusion bags to be packed, and inserts the assembled series of infusion bags in a packing container provided in a predetermined position or positions them accordingly. The feeder advantageously makes a continually rotating motion or a linear oscillating motion. In one embodiment of the invention, at least one feeder is arranged on a continually circulating belt or chain drive, with which a predetermined number of infusion bags assembled in a series of infusion bags is taken out of the shaft in a continually rotating movement as the feeder circulates and is fed to a packing container placed in a predetermined position. The assembled series of infusion bags is inserted into the packing container in another advantageous embodiment of the invention with the motion of the feeder or with a separate pusher.